Coal face support systems



Oct. 24, 1967 Filed Feb. 15, 1965 O. JACOBI GOAL FACE SUPPORT SYSTEMS 2Sheets-Sheet l INVENTOR I UsKAR' JABEJEI.

BY dw ATT 1 Y S Oct. 24, 1967 o. JACOB! 3,348,381

COAL FACE SUPPORT SYSTEMS Filed Feb. 15, 1965 2 Sheets-Sheet 2 INVENTOR.[I SKAR JAB DB 1.

BY WM.

I ATTYS- United States Patent 3,348,381 COAL FACE SUPPORT SYSTEMS OskarJacobi, Semperstrasse 24, Essen, Germany Filed Feb. 15, 1965, Ser. No.432,556 Claims priority, application Germany, June 4, 1964, B 77,067/646 Claims. (Cl. 61-45) ABSTRACT OF THE DISCLQSURE A method ofsuccessively advancing through a predetermined distance individualsupport units of a mine roof support system which are associatedtogether in groups. The method provides for the shifting of the units ina particular group upon the need for local support adjacent thatparticular group, therefore, the groups are not advanced in sequentialfashion. A group control means signals a unit control means of a groupupon the sensing of a localized need for support. The unit control meansthen activates the first support unit in its group and the units withinthe group are advanced in a predetermined sequence. After advancing ofthe last unit within the group, the first unit again becomes thecontrolling unit and awaits a signal from the group control means priorto reactivation.

The invention relates to a method for successively shifting and settingthe support units of a hydraulic coal face support system.

The method of the instant invention automatically secures the roof zonewhich is exposed at any given time, whether through the progress of themining process or through breaking away of the working face,independently of the attention paid by the miner and immediately afterthe roof zone has been exposed.

The invention provides a method which eliminates, in particular, thosedanger factors which occur as a consequence of the roof not beingsupported at all times locally. This is achieved by advancing thesupport system not only in accordance with the progress of the working,which is customary in itself, but by also providing that any intentionalor unintentional exposure of roof surface at any local point of theworking face shall result in local advance of the support system.

This type of coal mine support does not exist in the methods ofself-advancing step-by-step support heretofore employed, even when, inaccordance with the latest proposals, the support units are shiftedautomatically and systematically in known manner by remote control,after each particular area has been worked. In this prior art method theshifting process takes place either after a breast or length of face hasbeen worked, in which case that zone of the roof which is close to thecoal face is left without support for a comparatively long time overthis length, or not immediately after a strip has been worked butinstead in succession in the longitudinal direction of the coal face incorrelation with the advance of the winning machine. Even in the lattercase it is not possible to make allowances for local changes in theconditions at the coal face, such as may occur, for eX- ample, due toscraping or breaking away of the working face. This may happen bothduring a working shift and when the coal face is not manned. If such achange occurs during the night shift, for example, it is possible thatmany hours may elapse before the exposed roof zone can be secured again.

It is the primary object of the instant invention to provide an improvedmethod successively shifting and setting the support units of a coalface support system.

It is a further object to provide a method whereby any intentional orunintentional exposure of roof surface at any location along the workingface shall give rise to control signals causing local advance of thesupport system.

Further objects of this invention will become apparent from thefollowing specification and drawings, in which:

FIG. 1 is a diagrammatic plan view taken immediate- 1y below the roof ofa coal mine, showing the method of the invention, and having partsbroken away for clarity.

FIG. 2 is a diagrammatic view of a group control system.

FIG. 3 is a diagrammatic view of a single support unit control system.

Briefly, the method according to the invention consists in associating aplurality of support units of a hy draulic coal face support systemtogether in groups in a manner known in the prior art. All the groupssimultaneously seek contact with the working face and, in a firstembodiment, one of the support units of each group is always at leastpartially relieved of roof supporting pressure at any given time to suchan extent that, being under the forward pressure of a shifting device,it maintains contact with the advancing working face. The advancing unitof each group triggers a control device after completing an advancingmovement of a predetermined distance. The signal operatively effects theimmediate set ting of the support unit, which has just completed itsadvance, under the full roof-supporting load and also the successiverelief of pressure in, and shifting of, the following or second unit.The following or second unit may then be regarded as having taken theplace of the first unit as the controlling unit. After the second unithas completed its advancing movement through the predetermined distance,it ,actuates a control device and control system which sets thestructural components of the second unit under its full roof supportingload and relieves the roof supporting load of the next unit as it beginsits shifting or advancing movement. The process is repeated following onfrom unit to unit within the group in a predetermined cyclic sequence.

Thus, the support units associated together. in each group are shiftedprogressively in a sequence which is always constant as between therespective support units, until a support unit is reached which possiblyhas not yet completed its advancing movement but which has been relievedof roof supporting pressure by the signal transmitted by the precedingunit, whereupon the shifting process is halted in its progression fromsupport unit to support unit, until this suport unit has likewisecompleted its advancing movement of the predetermined distance and theshifting of the following support units is then carried on until, afterthe last support unit in the group has been shifted, a changeover backto the first unit is made automatically.

It will be clear that the result thus obtained is that the shifting ofeach unit in the group takes place automatically after the shifting ofthe preceding unit, provided the zone of the roof to which that unit isallocated has been exposed in accordance with the stepping move mentwhen one unit advances. The remaining support units in the group securethe roof under the full roof supporting pressure.

In this connection, it is advantageous that the particular unitperforming the stepping or self-advancing movement under the constantforward pressure of its shifting cylinder should be relieved of pressureonly to such an extent that the sliding forward thereof under the actionof the shifting device is just possible. Experience has shown that, withsuiltable dimensioning of the shifting cylinder, this is the case at asetting pressure of 2 to 5 tons, which is fully adequate for fulfillingthe purpose of protection against the falling-in of, for instance, looselining from the roof.

The number of support units which are suitably combined together to forma group is chosen according to circumstances. In the case where pairs ofprops are employed it will as a rule be about 6 to 10 pairs of props.

The new method can be applied to support both by means of frameassemblies and by means of supporting trestles or yokes, both of themeans being well known in the art.

Whether the shifting process is in the nature of an overhauling step ora follow-on step is of no importance from the point of view of the newmethod.

Normally a conveyor is disposed between the front vertical prop of eachsupport unit and the coal face. Therefore, it is advantageous, and as arule essential, in order to enable that unit which is the controllingunit at any given time to maintain contact with the working face, todesign the roof bars of the support units, which maintain contact withthe working face, so that they project forward comparatively far beyondthe conveyor.

When in spite of the roof bar projecting forward comparatively far, theprop of the unit which is on the side where the working face is locatedis about to engage or strike the conveyor and the unit has not completedits advancing movement, the prop engages, for example, a feeler switchwhich is mounted adjacent the conveyor and the switch deactivates thehydraulic control system, thereby stopping the shifting process. Thisoccurs before the predetermined stepping distance of the controllingunit has been reached so that the signal for further shifting is nottransmitted, thereby the greatest possible safety for the exposed roofzone is still always achieved. After the conveyor has been moved, thecontrolling unit is free to complete its advancing movement.

The progress of the process of shifting the successive support units inthe new method may be compared with a relay race in which many groupstake part, but only one unit is in motion in each group and in eachgroup group as a whole after the preceding one has run a predetermineddistance.

In order to render satisfactory shifting of the partiallypressure-relieved units and in order to prevent the floor or roof barfrom remaining behind, shifting cylinders are preferably provided bothin the roof region and in the floor region of the units.

The hydraulic, pneumatic or electrical control system which is requiredin order to produce the automatic occurrence of the various operations,namely, relief of pressure, shifting, and re-setting, in thechronological sequence prescribed by the invention, corresponds tosystems which are known in the art, for example, in the field of remotecontrol self-advancing support apparatus. Therefore, the control systemsknown in the art will not be described in detail in the presentapplication. Preferably, provisions are made in any type of controlsystem system and the controlling support unit is relieved of roofsupporting pressure at that time. Immediately the controlling unitadvances the predetermined distance and is reset under full roofsupporting load. The next support unit is then actuated and the aboveprocedure is repeated.

By means of an electric circuit or with a plurality of feeler devices itis also possible to cause the shifting operations within the group toproceed, not in a strict sequence, but in such manner that the unitwhich advances is always the one which has no contact with the coalface, while nevertheless there is always only one unit relieved ofpressure at one and the same time. 7

Referring to FIG. 1, a coal face is generally indicated by the referencenumeral 20. A plurality of support units 21 of a hydraulic coal facesupport system are associated together to form groups. In FIG. 1, threesuch groups are shown and indicated by the Roman numerals I, II, andIII. FIG. 1 shows diagrammatically various conceivable stages in theshifting operation as carried out by the method of the invention, whenapplied to the simple case of a fixed cyclic sequence, all details notessential to the understanding of the invention having been omitted.

FIG. 1 shows three groups of support units (I, II, and III) followingone on the other on the dip or Working, the groups each consisting often support units 21. For purposes of explanation the ten support units21, of each i group, are serially numbered from 1-10 in FIG. 1.

used in practicing the instant method for carrying out the controloperations manually when necessary or desired.

As described above, if the working face has not receded thepredetermined distance adjacent the controlling support unit, it ispossible that the controlling unit will remain partially relieved ofpressure fora long time while concurrently remaining under the constantforward pressure of the shifting device. This condition could exist, forexample, where the excavation of the coal face proceeded at anabnormally slow pace. To eliminate this condition, while practicing theinstant method, according to the preferred embodiment; a feeler deviceis mounted on the end of the controlling support unit. The feeler deviceis mounted adjacent the roof bar of the support unit, as describedbelow. The feeler device maintains continuous contact with the workingface. When the predetermined distance is sensed, the feeler devicesignals the control In FIG. 1, the roof support props are not shown buttheir location is indicated by circles drawn on top of the roof bars ofthe support units 21. If the circle is cross hatched, this indicatesthat the prop is under full roof supporting pressure. However, if thecircle is not filled the prop has been at least partially relieved ofroof supporting pressure.

The first group of support units (I) is in the initial state, that is tosay, all the support units 1 to 10 are in a' position close to theworking face. The topmost support unit 1 in this group (I) which in thecondition shown constitutes the controlling unit, is relieved ofpressure. Under the constant forward pressure of its shitting cylinderthe unit 1 is in contact with the working face 20. Its roof bar ispressed constantly against the working face 20.

However, in the preferred embodiment, the controlling support unit, inthis instance the unit 1, is not relieved of pressure until thepredetermined advancing movement is sensed by the feeler device. Oneembodiment of a known feeler device is generally indicated in FIG. 2 bythe reference number 25. A known pneumatic group control system isgenerally indicated by the reference number 26 and a known frame orsupport unit control system is indicated by the reference number 27. Thefeeler device 25 includes a pneumatic cylinder 30 which is mountedadjacent a roof bar of, for example, the support unit 1. The cylinder 30includes a piston 31, a piston rod 32, which mounts a feeler 33, andfluid ports 34 and 35. A projection 36 having a cam surface 37 isconnected to the rear of the piston rod 32. V

A three way valve 3-8 having a valve spool 39 is mounted adjacent thecylinder 30. A valve activating rod 40 extends outwardly from the valve38 in a position where it can be engaged by the cam surface 37.

The group control 26 includes a cyclic timer unit 41 which directscompressed air from an air supply line 42 to conduits 43, which are incommunication with the controlling unit of each of the groups, forexamples, the groups I, II and III.

As depicted in FIG. 2, the air supply line 42 is in communication with aconduit 44 through the unit 41, and the conduit 43a. The conduit 44 isconnected to the port 35 of the cylinder 30 and a conduit 45 extendsfrom the conduit 44 to the valve 38.

A constant pressure airline 46 is connected to the port 34 of thecylinder 30. An air conduit 47 extends between the valve 38 and thesupport unit control system 27 and a conduit 48 extends outwardly fromthe valve 38.

In operation, the constant pressure air from the airline 46 urges thepiston 31 to the right. FIG. 2 depicts the condition immediately afterthe cyclic timer 41 has operatively connected the conduit 44 to thesupply line 42. The compressed air of the supply line 42 is of a higherpressure which overrides the air pressure from the airline 46 and thepiston 3-1 is urged to the left (as shown in FIG. 2). As the feeler 33moves to the left, if it moves the predetermined advancing distanceprior to engaging the coal face, the cam surface 37 strikes the valveactivating rod 40. This moves the valve spool 39 downwardly placing thesupply line 42 in communication with the air conduit 47 which activatesthe individual support unit control system 27 as described below.

On the other hand, if the feeler 33 does not move the predetermineddistance, when the timer 41 cycles to the next group, the air pressurein the conduit 44 collapses and the piston 31 moves to the right. Whenthis occurs, the individual unit control system 27 of group II is notactivated.

It should be noted that when the individual control system is actuated,the group control 26 does not wait until the all of the individualsupport units (1-10) in the group II have been activated, but rather,cycles throughout the feeler devices of the remaining groups so thatlocalized support is provided by any group in which the coal face isspaced the predetermined distance, irrespective of the position of thatgroup with respect to the remaining groups.

Referring to FIGS. 2 and 3, if the valve spool 39 is moved downwardly,air is supplied to the conduit 47 leading to the respective unit controlsystem 27. A valve 50 in the conduit 47 is activated and a supply line51 is placed in communication with a conduit 52 which leads to astepping relay 53 of the unit control system 27. The air pressureactivates the relay 53 and moves a controller 54 from a start positionindicated by the dashed line position 54 to the full line position,wherein the number 1 support unit, of the support units 21, isactivated.

Each of the support units 21 includes a control device 55 which in thepresent embodiment is in electrical communication with the steppingrelay 53.

A pair of roof props 56 having roof bar rarns and an advancing cylinder,all of which are well known in the art, are operatively connected to thecontrol device 55. Upon activation of the number 1 support unit, itsrams are depressurized, and its advancing cylinder is operated advancingthe props 56 the predetermined distance. Upon advancing the rams arerepressurized and the control device 55 is triggered therebytransmitting a signal back to the unit control system 27 The steppingrelay 53 is activated and the controller 54 is operatively connected tounit number 2. The process is repeated from unit to unit in apredetermined sequence until the start position, indicated by the dashedline position of the controller 54, is reached. At this time, air issupplied through a conduit 58 and through the conduit 48 to shift thevalves 50 and 38. Unit number 1 is again the control unit at this timeand is reactivated upon the sensing of the predetermined distance by thefeeler device 25 of group II as described above.

As previously mentioned, if during the advancing movement the props 56contact the conveyor, indicated by the reference number 60 in FIG. 3, afeeler switch is activated which transmits a signal to the respectivecontrol device 55 which stops the shifting movement. Movement withinthat particular group does not begin again until the conveyor 60 hasbeen moved.

According to the embodiment, the middle units 4 to 7 of group I areopposite an excavation in the working face and therefore do not have anycontact with the face 20. In this example they cannot be shifted beforeall the preceding units have been shifted. As previously mentioned, itis possible to allow for this by using a special electric circuit. Asthe entire length of the group of support units 1 to 10 along the dipmeasures only about 8 metres, no moments of danger occur because ofthis. By choosing smaller groups the roof areas which may possibly beunsupported can be further reduced. In the case of this example, theshiftingsignal for the unit 1, which signal initiates the shiftingprocess of the entire group, is transmitted only when either theexcavation shown has advanced to a point beyond that zone of the face 21to which the unit 1 is allocated, or the corresponding roof zone hasbeen exposed by the winning operation.

In the first case, on the assumption that the extent of the excavationremains unchanged at the lower end of the section to which the group Iis allocated, the shifting process would continue only as far as theunit 7, while successive shifting of the remaining units 8 to 10 wouldmean that the roof zone would be exposed in this region also.

In the case of the second group (II), the drawing shows that the upperunits 1 to 4 of the group (II) have already been progressively shiftedthrough the predetermined distance and the unit 5 has been relieved ofpressure by the signal transmitted by the unit 4 (this being indicatedby the circles which represent the props not being filled in). In thestate of the working face illustrated, in which the corresponding roofzone is exposed, such unit 5, after being shifted the stepping oradvancing distance and being set by the signal then produced so as totake full load, transmits the shifting signal for the following units 6to 10.

In the case of the third group of support units (III), it is assumedthat the topmost unit 1 has been relieved of pressure and has alreadybeen partially shifted but has not yet completed its prescribedadvancing movement, because it has already been brought to a stop by theinsufficiently exposed face before it has traveled its predetermineddistance. Thus, this unit remains relieved of pressure and under thecontinuous action of its shifting mechanism which presses it forwarduntil such time as the adjacent roof zone has been exposed, whereuponthe process is continued as has been described.

The instant invention provides for automatically and immediatelysecuring to as great an extent as possible the zone of the roof which isexposed by excavation from the face 20. Only a single support unit isrelieved of pressure at any one time and it is only partially relieved.As such it still can perform its roof supporting function.

Of course, the invention is not limited to the particular manner ofcarrying it into effect described above in detail. Thus, in cases whereit proves to be expedient, the sequence in which the support units areshifted can be varied. For example, instead of the controlling unitcontrolling the unit immediately adjacent to it, the next unit isby-passed and the following unit is controlled. The control operationthereafter may revert to the intermediate unit if this proves to beexpedient in certain circumstances, for example in order to avoidloading of partially pressure-relieved frames due to convergenceeffects, such as would prevent the shifting operation. In thisarrangement likewise, the control signal is always transmitted in thesame direction in a closed cycle.

What I claim is:

1. A method of automatically and successively advancing through apredetermined distance individual support units of a mine roof supportsystem which are associated together in groups, the groups beingcontrolled by a group control means, and wherein the individual supportunits within each group are controlled by unit control means, comprisingtransmitting a signal from the group control means to the unit controlmeans of each group which is spaced the predetermined distance from theworking face, whereby the unit control systems are actuated upon thelocalized sensing of the predetermined distance rather thansequentially, each of said actuated unit control means transmitting asignal to a first one of its individual roof support units, relievingthe first support unit of its roofsupporting pressure, advancing thefirst support through the predetermined distance, triggering the unitcontrol means, resetting the first unit under its roof-supportingpressure, relieving the second one of the individual roof support unitsof its roof-supporting pressure, the unit control means relaying controlsignals from unit to unit until the last unit is reached whereupon thefirst unit again becomes the controlling unit and is reactuated upon asubsequent signal from the group control means.

2. A method according to claim 1, wherein the signal transmitted by thegroup control means occurs upon sensing of the predetermined distancebetween the controlling support unit of a group and the coal face byfeeler means.

3. A method according to claim 1, wherein within each group, the controlsignals for the advancing action are transmitted from unit to unitsequentially in one direction only, from the first unit of the group asfar as the last unit thereof, and from this last unit back to the firstunit.

4. A method according to claim 1 wherein the particular individualsupport unit performing the advancing action at anytime is relieved ofpressure only by the amount which permits it to slide forward under theaction of its shifting device.

5. A method according to claim 1 wherein conveyor means are positionedbetween the support units of the group and the coal face, including thestep of stopping the advancing movement of the individual support units;upon engagement of the advancing unit and the conveyor means.

6. A method for supporting amine root with a hydraulic working facesupport system having a plurality of support groups controlled by agroup control system, each of the support groups; comprised of aplurality of individual support units which are controlled by a supportunit control system, each of said support units hav ing shifting meansfor advancing the unit toward the working face and prop means operableat various roof supporting pressures, comprising, transmitting a signalfrom the group control system to at least one of the support groups toactivate individual ones of the support unit control systems, wherebythe individual support unit control systems are actuated upon a need forlocalized roof support rather than sequentially, at least partiallyrelieving a first one of the support units from the support group of itsfull roof-supporting pressure, subjecting the relieved first supportunit to a continuous forward shifting pressure, moving the firstroof-supporting unit toward the working face a predetermined distance,triggering the support unit control system upon completion of themovement of the first unit through the predetermined distance, wherebythe support unit control system effects the setting of the first unitunder its full roof supporting load and relieving a second support unitof the group from its full roof supporting pressure, whereby said secondunit is the controlling unit, the support unit control system relayingcontrol signals for the advancing action from unit to unit in apredetermined sequence until the last unit is reached whereupon thecontrol signal is relayed back to the first unit.

References Cited UNITED STATES PATENTS 3,202,058 8/1965 Bolton et al.6l45.2 X 3,243,964 4/ 1966 Thomas et al 6145.2 X 3,259,024 7/ i966Kibble et al. 6l45.2 X 3,272,084 9/1966 Bolton et al. 6145.2 X

DAVID J. WILLIAMOWSKY, Primary Examinen JACOB SHAPIRO, Examinem UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,348,381October 24, 1967 Oskar Jacobi ror appears in the above numbered pat- Itis hereby certified that er the said Letters Patent should read as entrequiring correction and that corrected below.

Column 1, line 63, for "scraping" read scarping column 2, line 10, after"the" insert instant line 51, for "suport" read support line 71, for"suiltable" read suitable column 3, line 40, after "group", secondoccurrence, insert one unit relieves the preceding one in the motion ofthe Signed and sealed this 12th day of November 1968.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A METHOD OF AUTOMATICALLY AND SUCCESSIVELY ADVANCING THROUGH APREDETERMINED DISTANCE INDIVIDUAL SUPPORT UNITS OF A MINE ROOF SUPPORTSYSTEM WHICH ARE ASSOCIATED TOGETHER IN GROUPS, THE GROUPS BEINGCONTROLLED BY A GROUP CONTROL MEANS, AND WHEREIN THE INDIVIDUAL SUPPORTUNITS WITHIN EACH GROUP ARE CONTROLLED BY UNIT CONTROL MEANS, COMPRISINGTRANSMITTING A SIGNAL FROM THE GROUP CONTROL MEANS TO THE UNIT CONTROLMEANS OF EACH GROUP WHICH IS SPACED THE PREDETERMINED DISTANCE FROM THEWORKING FACE, WHEREBY THE UNIT CONTROL SYSTEMS ARE ACTUATED UPON THELOCALIZED SENSING OF THE PREDETERMINED DISTANCE RATHER THANSEQUENTIALLY, EACH OF SAID ACTUATED UNIT CONTROL MEANS TRANSMITTING ASIGNAL TO A FIRST ONE OF ITS INDIVIDUAL ROOF SUPPORT UNITS, RELIEVINGTHE FIRST SUPPORT UNIT OF ITS ROOFSUPPORTING PRESSURE, ADVANCING THEFIRST SUPPORT THROUGH THE PREDETERMINED DISTANCE, TRIGGERING THE UNITCONTROL MEANS, RESETTING THE FIRST UNIT UNDER ITS ROOF-SUPPORTINGPRESSURE, RELIEVING THE SECOND ONE OF THE INDIVIDUAL ROOF SUPPORT UNITSOF ITS ROOF-SUPPORTING PRESSURE, THE UNIT CONTROL MEANS RELAYING CONTROLSIGNALS FROM UNIT TO UNIT UNTIL THE LAST UNIT IS REACHED WHEREUPON THEFIRST UNIT AGAIN BECOMES THE CONTROLLING UNIT AND IS REACTUATED UPON ASUBSEQUENT SIGNAL FROM THE GROUP CONTROL MEANS.